Lighting systems in the prior art are typically formed by interconnecting, via a communications system, a plurality of lighting fixtures and providing for operator control of the plurality of lighting fixtures from a central controller. Such lighting systems may contain multiparameter light fixtures, which illustratively are light fixtures having two or more individually remotely adjustable parameters such as focus, color, image, position, or other light characteristics. Multiparameter light fixtures are widely used in the lighting industry because they facilitate significant reductions in overall lighting system size and permit dynamic changes to the final lighting effect. Applications and events in which multiparameter light fixtures are used to great advantage include showrooms, television lighting, stage lighting, architectural lighting, live concerts, and theme parks. Illustrative multi-parameter light devices are described in the product brochure entitled “The High End Systems Product Line 2001” and are available from High End Systems, Inc. of Austin, Tex.
A variety of different types of multiparameter light fixtures are available. One type of advanced multiparameter light fixture is an image projection lighting device (“IPLD”). Image projection lighting devices of the prior art typically use a light valve or light valves to project images onto a stage or other projection surface. A light valve, which is also known as an image gate, is a device for example such as a digital micro-mirror (“DMD”) or a liquid crystal display (“LCD”) that forms the image that is projected. Either a transmissive or a reflective type light valve may be used. U.S. Pat. No. 6,057,958, issued May 2, 2000 to Hunt, incorporated herein by reference, discloses a pixel based gobo record control format for storing gobo images in the memory of a light fixture. The gobo images can be recalled and modified from commands sent by a control console. A pixel based gobo image is a gobo (or a projection pattern) created by a light valve like a video projection of sorts. U.S. Pat. No. 5,829,868, issued Nov. 3, 1998 to Hutton, incorporated by reference herein, discloses storing video frames as cues locally in a lamp, and supplying them as directed to the image gate to produce animated and real-time imaging. A single frame can also be manipulated through processing to produce multiple variations. Alternatively, a video communication link can be employed to supply continuous video from a remote source.
U.S. Pat. No. 5,828,485, issued Oct. 27, 1998 to Hewlett, incorporated herein by reference, discloses the use of a camera with a digital micro mirror equipped light fixture for the purpose of following the shape of the performer and illuminating the performer using a shape that adaptively follows the performer's image. A camera capturing the image (such as a digital camera, which captures an image at least in part by storing digital data in computer memory, the digital data defining or describing the image) preferably is located at the lamp illuminating the scene in order to avoid parallax. The image can be manually investigated at each lamp or downloaded to some central processor for this purpose.
U.S. Pat. No. 5,988,817 to Mizushima discloses a mulitprojection system that can be controlled by a lighting controller that is capable of producing a single image with a plurality of projectors.
IPLDs of the prior art use light from a projection lamp that is sent though a light valve and focused by an output lens to project images on a stage or a projection surface. The light cast upon the stage by the IPLD is then imaged by a camera. U.S. Pat. No. 6,219,093 to Perry titled “Method and device for creating the facsimile of an image”, incorporated herein by reference, describes a camera that may be an infrared camera for use with a described lighting device that uses liquid crystal light valves to project an image. “Accordingly the camera and light are mounted together for articulation about x, y, and z axes as is illustrated in FIG. 1” (Perry, U.S. Pat. No. 6,219,093, col. 4, line 59).
In their common application, IPLDs are used to project their images upon a stage or other projection surface. The control of the various parameters of the IPLDs is affected by an operator using a central controller. In a given application, a plurality of IPLDs are used to illuminate the projection surface, with each IPLD having many parameters that may be adjusted by a central controller to create a scene.
IPLDs used in an entertainment lighting system can produce many colorful images upon the stage or projection surface. IPLDs may project images onto the projection surface such as still images, video images and graphic images. The term “content” is a general term that refers to various types of creative works, including image-type works and audio works. Content is typically comprised of still images, video images or loops and computer graphical images.
The Catalyst image projection lighting device manufactured by High End Systems of Austin Tex. incorporates a video projector with a moveable mirror system that directs the images projected by the projector onto the stage or projection surface. A personal computer is used as a server that provides the images to the projector. A lighting controller sends command signals over a communication system to control the selection of images from the server to the projector as well as control the various functions of the video projector and the position of the image on the projection surface. An operator of the lighting controller may modify content before it is projected by sending commands to a personal computer image server. Some examples of the types of modifications to the content are image rotate, negative image, image strobe, image zoom and RGB control. The different types of modifications of the content material can be referred to as “effects”. An operator of the lighting control system can send commands to the Catalyst image server over the communication system to adjust or select the effects that modify the content that is projected as an image.
Often times an IPLD projecting an image on a stage or projection surface must transition from a first image that is being projected to a second image. This is accomplished by reducing the RGB (red, green, blue) levels of the first image until the first image fades to black on the projection surface. Next the IPLD content is changed so that the second image to be projected is available to the image control but since the RGB levels are still reduced to achieve a fade to black, the transition from the first image to the second image is not seen by the audience viewing the projection surface. Next the RGB intensity levels are controlled to be slowly raised to reveal the second image. The method of fading down the first image to black by reducing the RGB levels, changing content and fading the second image up to reveal the second image by increasing RGB levels produces a smooth fade up and down transition of the first image to the second image. The transition can be distracting to the audience viewing the transition on the projection surface, however, since for a moment during the transition between the first image and the second image the projection surface was not illuminated by projected light from the IPLD during the fade to black.
U.S. Pat. No. 6,208,087 to Hughes titled Pixel Mirror Based Stage Lighting System and 6,188,933 to Hewlett titled Electronically Controlled Stage Lighting System disclose a technician port servicing an image projection lighting device. The preferred hand held terminal for the technician port is a micropalm having a gray scale display.
The manufacturers of video projectors sometimes used with IPLDs of the prior art, often include a zoom and focus motor system however they are often not robust enough for the frequent adjustments of zoom and focus required for a lighting show. The remote zoom and focus system that is built into the video projector many times does not have any type of positioning by a sensor that would help guarantee that the zoom and focus lens positions are highly accurate when recalling a preprogrammed focus or zoom value from the central controller. U.S. Pat. No. 5,988,817 to Mizushima discloses the use of external motors for zoom and focus on a video projector. The external motors and belts used on the zoom and focus lens incorporated on the sled of the system disclosed by Mizushima require an increase to the overall size of the sled length.